net: smc91x: fix neponset breakage by pxa u16 writes

The patch isolating the u16 writes for pxa assumed all machine_is_*()
calls were removed, and therefore removed the mach-types.h include which
provided them.

Unfortunately 2 machine_is_*() remained in smc91x.c file including
smc91x.h from which the include was removed, triggering the error:
 drivers/net/ethernet/smsc/smc91x.c: In function ‘smc_drv_probe’:
 drivers/net/ethernet/smsc/smc91x.c:2380:2: error: implicit declaration
 of function ‘machine_is_assabet’
 [-Werror=implicit-function-declaration]
	if (machine_is_assabet() && machine_has_neponset())

This adds back the wrongly removed include.

Fixes: d09d747a ("net: smc91x: isolate u16 writes alignment workaround")
Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>